The long-term objectives of the research proposed are to determine the biological consequences of exposure to ultrasound on mammalian development. The proposed studies will evaluate the effects of ultrasound exposure of the ovary, by means of assessing preimplantation embryonic development in the mouse. Using this model, experiments have been designed to examine the effects of different levels of ultrasound on cell division, DNA synthesis, protein synthesis and the appearance of temporally- regulated cell surface molecules in the early embryo.